


Their first time

by xxxhunter



Category: Thundercats (2011), Thundercats - All Media Types
Genre: Brother/Sister Incest, Creampie, F/M, Fluff and Smut, Incest, Sibling Incest, Teen Romance
Language: English
Status: Completed
Published: 2018-10-19
Updated: 2020-01-08
Packaged: 2021-02-27 07:48:50
Rating: Explicit
Warnings: No Archive Warnings Apply, Underage
Chapters: 3
Words: 8,179
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22173577
Author URL: https://archiveofourown.org/users/xxxhunter/pseuds/xxxhunter
Summary: After spying on something they shouldn't have, Wilykit and Wilykat try to imitate what they saw. This is the story of two teenage siblings exploring their newfound sense of sexuality together, their first time.
Relationships: wilykit/wilykat
Comments: 3
Kudos: 19





	1. Spying

**Author's Note:**

> NOTE : the first two chapters are simply the setpieces. Sex start at the third chapter   
> Based on their 2011 designs. Contain graphic Incest and underage sex. smut/lemon. Age of the characters : 14-ish and up. Contains the following pairings : wilyKit/wilyKat, Cheetara/Tigra (mention), Lion-O/Pumyra (mention).

**Spying**

* * *

Wilykit was walking around the Thundertank, deep in her thoughts and her tail kept low, thinking back to everything that led to what she just saw.

She admired Cheetara, her bravery, her strength, her beauty. She is her role model and wanted to emulate her. She had noticed over time how Tigra and Cheetara often isolated themselves from the rest of the Thundercats and Wilykit wanted to discover what they were doing all these times.

She took notice of the most common place they isolated themselves, their locked room in the Thundertank, and planned meticulously how she was going to hide and not be found, the timing of it so she could be there and witness what they were hiding.

She saw it all.

What was it they called it?

Sex

She saw Cheetara’s beautiful naked form, a form she hoped one day to reach, to develop into, mounting Tigra.

She saw their passion

their pleasure,

their ecstasy

That shook her.

Once she could safely get out of her hiding place, she was already deep in her thoughts. She wasn’t sure at first how to feel about it but after a while, deep down, she knew she now wanted to feel what they felt too, she wanted to feel what Cheetara felt.

Wilykit had never really thought about the “boy’s mystery” before but after what she saw, she was now considering it. She knew that none of the older Thundercats would give her the time of day, especially not about something she knew was intimate and must be kept secret, considering how Tigra and Cheetara isolated themselves.

A small tinge of sadness crossed her heart. The Thundercats were always moving from place to place, fighting Mumm-Ra’s army and schemes. There was not much place for long term socialization. They often met politicians, leaders and warriors, not civilians. And when they helped a village, they never stayed long afterward.

Wilykit never had the time to meet a boy her age. She didn’t knew anyone.

Except her brother

\-----------------------------------------------------------------------------------------------------------------

Wilykat was deep in thoughts, his tail kept low.

While his sister took Cheetara as role model, he took Lion-O as his. Although he wished to be as cool as Tigra, he admired Lion-O’s bravery through adversity, his leadership and his courage to keep on fighting even when things felt hopeless.

Unbeknownst to him, he noticed the same thing as his sister, how Lion-O and Pumyra isolated themselves just like Tigra and Cheetara. He even cooked up a plan quite similar to Wilykit’s.

He saw the same thing she did.

He saw Lion-O having sex with Pumyra.

He saw it all.

The same thoughts as his sister assailed him. He wanted to experience what he saw. He wanted to feel that passion, that love. He had a feeling that none of the older Thundercats would give him the time of day for such a subject... such a secret.

He had reached the same conclusion.

He didn’t knew any girl his age

Except his sister.

\-------------------------------------------------------------------------------------------------------------------

The young teenaged Thunderkittens where in their common bedroom, in the Thundertank, sitting there in awkward silence, their tails moving hesitantly.

After many hesitations and dancing around the subject, they opened themselves to each other about what they saw, what they witnessed, in all their youth’s awkwardness.

Siblings hold no secrets to each other, afterall.

Now they sit there, silent, unknowing about what to say next.

Wilykat was the first to break the silence.

“So huh.... I guess we had made the same hiding plan.”

“Yeah” was all that Wilykit replied.

“You sure they didn’t notice you?”

“Yeah.

Made sure they really where gone before getting out of the spot and room.”

“And you, you sure you didn’t made a sound?”

“Certain.”

Silence

Wilykat broke the silence again

“Now what?”

“What do we do?”

“What can we do?”

said Wilykat a little louder yet with a slight but noticeable stutter in his voice.

Wilykit noticed it

“Are you.... are you afraid?”

“If I am?.... but Sis...”

Wilykat couldn’t finish that sentence; he only could produce a few grunts.

“Wilykat...”

Wilykit said as she put her hand on her brother’s arm.

“You can tell me.”

A look of fear mixed with sadness passed Wilykat’s face; he simply couldn’t hold back his feelings inside him in front of his sister, his tail moving frantically, as if to better illustrate his inner turmoil.

“Yes, im afraid Sis.

Afraid of what the others would say if we told them what we saw.

Afraid of being brushed off because ‘we are too young’.

Afraid of being told to forget something that looked so... so... ...”

Wilykat had a hard time finishing that thought but his sister’s empathic smile she gave as she was looking at him pushed him just enough to finish it.

.....great.”

Wilykat continued but she stopped listening.

Wilykit knew those fears very well. Afterall, she had the same fears deep inside her.

A fear of the others’ reactions.

Yet deeper still...

A fear that she could never experience the same thing as what she was a witness to.

A fear that she could never reach the same level as her role model who did it.

They couldn’t tell about that experience to anyone else.

She wanted to experience what she saw, just like Wilykat.

But all she had was….. her…. Brother?

A fleeting thought passed her mind but it went too fast for her to grab it.

Until Wilykat continued his confession with this :

“....and I don’t know any girl my age with who I could tell or do this with!”

Wilykit reflexively replied :

“But Kat, **I AM** here.”

Wilykat forgot what he was going to say next to look at his sister.

Did she really say what he just heard?

Wilykit brought her hand to her mouth. She had said that reflexively, to try and assuage Wilykat’s fears.

She realized it could mean something else in that context.

Yet....

“Kat, I.... am... here”

Repeating the words brought something, a thought, almost within her reach yet something she still needed a slight push to fully grasp. Wilykat would give that final push.

“A girl.... my age...... I could do it with......?”

It wasn’t a perfect repetition but it was something that finally formed what the siblings were starting to think.

Those were the words that brought the final realization.

They looked at each other, in silence, yet their thoughts raging and spinning rapidly behind it.

It finally formed something coherent.

Something concrete they could understand.

Something they could act upon.

Wilykit was the first

“We have.... each........ other....”

Something clicked in Wilykat.

He hadn’t thought about his sister for this......yet there she was....... perfect

She was always there for him.

They did everything together.

They were often considered simply “the kids” amongst the Thundercats, so more often than not, they only had each other.

He now realized it

She would be there with him for this too.

This “sex” thing


	2. Planning

**Summary for the Chapter:**

> The Thunderkitten twins now plan for everything they could reasonably plan for, according to their limited knowledge, and make sure that their "activity" goes unimpeded.

**Planning**

* * *

This was a few days after the Thunderkittens reached the same conclusion.

The conclusion that, for them to experience the passion they were both witness to, this “sex” thing, what they needed was .... each other.

Yes, the siblings were now planning to have sex with each other.

They had no moral compulsion against it because, for one, they lost their parents and the rest of their family to a raid by Mumm-Ra’s forces years ago. Too early for them to reach the stage in their life where they would be curious of sex and where they would get “the talk”. The word “incest” was indeed foreign to them. Being tailed Thundercats also didn’t help since those where usually discriminated upon by tailless Thundercats so no one wanted to bother themselves with them, until they joined their current group, with Lion-O and the others.

Another reason was that they considered having sex with each other the same way siblings would explore things together. They did not truly understood everything it entailed or the intense feelings it would shower them with.

To them, it would just be another fun thing to do between brother and sister,

It would just be more... intimate... and secret.

And so they took a few days to really plan it.

They needed a place quite comfortable that could be locked tight, where they would not be interrupted, where the others wouldn’t find it odd for them to be there and where it wouldn’t be awkward to move.

Their common bedroom in the Thundertank would be good enough.

They had tried to bring their beds together for a larger bed surface but they were fixed to the floor of the Thundertank so they will have to make do on just one.

They could have planned about what to do with the soiled bedsheets after the act but that was the one thing that they didn’t pay attention to in their spying so they did not know to plan for it.

Next step, they needed to check if their room was sufficiently noise-proof so that the other Thundercats would not hear them. They did notice that when the others had sex, they tended to be loud afterall but they didn’t know what those outside the room heard.

Wilykit was inside their room while Wilykat was outside their door, in the middle of the corridor.

Wilykit was screaming at the top of her lungs while Wilykat listened to what he could hear.

A small strident noise.

Others could hear it but he remembered the scene he witnessed and thought that the noise made then wasn’t as loud as his sister screaming now so there was a good chance no one will even hear the weaker noise.

Wilykat was about to move when he noticed that Panthro was beside him, walking toward the front of the Thundertank.

He was too concentrated on hearing his sister to pay attention to Panthro walking down the corridor.

“What are you doing?” asked the giant man

“Oh, just making sure we don’t bother you with our noise.” Replied Wilykat, a shock dawning on his face.

He couldn’t believe what he just said!

In his nervosity, he just betrayed that he and his sister where planning something!

However....

“Ok”

That was all that replied Panthro, obviously having other things to think about than to worry about the kids.

Wilykat was immediately relieved : his blabbermouth wouldn’t bite them back.

Panthro simply continued to walk toward the front of the Thundertank.

However, soon after reaching it, a thought crossed his mind.

“Wait a minute.... what does he mean by ‘not bothering us’?”

But after a few seconds of pondering he said to himself.

“Whatever”

As long as they don’t make a mess or damage the Thundertank, it’s not his problem. Otherwise, he’ll work them to the bone until they clean up THEIR mess from HIS vehicle.

\--------------------------------------------------------------------------------------------------------------

Back with the Thunderkittens, everything was going smooth. They finished their plan and covered all the issues they knew about.

All that was left was choosing a time where they will have plenty of time for their act, their incest; where it will be early enough so that they won’t be too tired too early and where the others won’t question their absence.

Everything they could reasonably plan for was ready.

**They** were ready.

**Notes for the Chapter:**

> I have rarely seen a smut fanfic that delved into the planning of a sex session. This way, no unwanted surprise. Just the action, unimpeded.  
> On a side note, I think I portrayed Panthro's gruffness reasonnably well


	3. Their first time

**Summary for the Chapter:**

> Enough talk! Have at them!

**Ready? ACTION!**

* * *

This is it!

The moment for the siblings’ first time.

Things are promising to be..... awkward?

There the young teenagers stood, in the middle of their room, fidgeting, not knowing how to actually start.

The door is locked, they have the time, they already removed their footwear and accessories, they won’t be bothered and they both want it.

But the only examples they have are two experienced couples, already comfortable with each other. Not first timers like them.

Wilykit first spoke while fidgeting

“So... huh.... what now?”

Wilykat replied, trying to remember what he saw when he spied.

“well... err....I remember that......humm.... Pumyra and Lion-O... kissed each other... at first.”

“So... you want a kiss?” hesitated Wilykit

“...yes”

Wilykit was gathering up her courage and started to lean in when Wilykat specified :

“They kissed.... on the... mouth.”

Wilykat couldn’t help but blush as he said that last word

Wilykit stopped, giving herself the time to process that thought. True, she had seen Cheetara and Tigra kissing on the mouth.

But herself doing that.... that was a big step for her.

Wilykat was fidgeting on place, averting his eyes from his sister, suddenly finding the floor fascinating.

Then Wilykit, having gathered her courage, leaned forward and gave him a small peck on his closed lips.

Wilykat was startled a bit. There was still a physical distance between them but the ice was broken.

Wilykit had a tinge of sadness. She could tell from her brother’s face that he was unsatisfied by just this.

He was about to speak up when she asked :

“So... huh.... how did they do it?”

That gave Wilykat a better focus on his thoughts, on what he wanted to say.

“Well Kit,...they... were close.....and they were hugging ......differently.... and then they kissed on the.... mouth..... for a while.”

All the while Wilykat was talking, they acted.

With lots of hesitation, they closed the small distance between themselves, traversing the physical and metaphorical space separating them.

Their bodies, filled with nervosity and with a small jump at first contact, soon touched each other.

They put their arms around each other with hesitation, slowly, little by little. Their tails where now going around each other’s body. They moved their hands around, not knowing where to put them. Going by the memories of what they had seen, they soon put them at appropriate places for the situation, the hug finally evolving into a true embrace.

They now realized that their faces where only centimetres from each others.

Blushing profusely, they readied their lips for a kiss, closing in the small distance left.

They approached a bit before backing up, still being a bit jumpy but the hesitation eroding little by little.

Their lips soon made a slight contact before they backed up a little again.

After one last look in each other eyes, feeling the care they have for each other and the last scrap of their hesitation evaporating...

They locked lips

They did not know how long they stayed like that.

They did not know about locking tongues with each other yet.

They couldn’t know.

They didn’t.

Each put one hand behind the head of the other, as if trying to be closer to each other, to force just a little bit more.

Trying to be closer.... closer than they have ever been.... as if to be closer than just being brother and sister.

Their first true kiss, full of the awkwardness of beginners yet filled with the raw passion of youth.

Filled with the budding feelings of true lovers.

After what felt an eternity, they separated, gasping for air, huffing and puffing.

They looked at each other, their eyes filled with a new love, knowing that there was no going back.

Going back from what? They did not know.

But they wanted this.

They finally separated themselves from their embrace. It was time to remove their clothes.

The hesitation came back.

Much weaker but it was still there.

They had seen each other naked before but not like this, not in this context and certainly not with the feelings of lust and love that was now starting to grasp their bodies and soul.

\-------------------------------------------------------------------------------------------------------

Wilykit was the first to make a move and removed the thin fabric covering her chest, showing her brother her budding breasts.

Wilykat was fascinated by what he saw: his sister was baring her breasts just for him.

He tried to look at them very closely but having to lean slightly forward to do that was physically awkward.

He sat on the bed they planned on using and motioned for his sister to come closer.

She did something he really didn’t expect and literally sat on his lap, her tail between his legs.

She had felt it was the correct thing to do but now they were blushing awkwardly. Still, her breasts were now close enough so Wilykat could look at them closely.

Wilykit’s teenage breasts already formed decent mounds. Not quite big enough for Wilykat to have a handful but big enough to show up even when she is clothed with her top, now that he thinks about it.

He put his hands on them and started playing with them. Wilykit squirmed a bit but let him do it.

While kneading his sisters’ breasts, he was enjoying how they felt, soft on certain aspects yet firm on others. He would have continued enjoying fondling them if another aspect didn’t catch his attention.

Wilykit’s nipples where standing straight, pointing toward Wilykat, almost like they were inviting him closer.

He let go of her left breast and put his now freed hand behind his sister to help her steady her position and so, he was now free to get a closer look at her nipple. He looked at the beautiful inviting shape, like it was daring him to suck on it.

And so he did.

Wilykit couldn’t help but let go a small gasp when her brother took her nipple in his mouth. However, she soon started to enjoy the feeling her brother gave her as he sucked on it. Him fondling her breasts was an enjoyable feeling, a feeling she didn’t knew before, especially not like that, but him sucking on her nipple was on another level entirely.

They stayed like that for a moment, Wilykat sucking on his sister’s breast while his other hand was trying yet failing to fondle her breast, now that he didn’t pay much attention to it. Wilykit meanwhile was trying to hold back some small noises while enjoying those new found sensations that were rolling around in her.

However, after a while, her nipple was now getting sore. She signified it to her brother with a light tap on the shoulder.

He let go of her breasts to look up to her, her nipple covered in slob, free from his mouth.

Even with his mouth slobbering she still found him lovely.

She kissed him again, not caring about the saliva, even finding the kiss more enjoyable tough this might have just been the spur of the moment.

A sister sitting on her brother’s lap, kissing him.

\-----------------------------------------------------------------------------------------------------------

That kiss was much shorter than the first and Wilykit soon stood back up.

She looked playfully at her brother, her tail moving with some anticipation.

“Hey Kat, I think it’s time for your turn. Time to remove your top!”

With no hesitation, Wilykat removed his shirt.

Wilykit felt some disappointment.

She remembered that Tigra had removed his slowly, like he was making a show for Cheetara, who seemed to enjoy the spectacle. Wilykat just removed it like it was something ordinary.

Still, she now had a good look at her brother’s torso. She looked at it with new eyes. He was fit but not muscular, befitting of someone using his speed rather than his strength.

Although it was a good look, she wasn’t satisfied. She had made the first move, so it’s his turn to make the next.

“Mmmm.... not bad.” She said playfully

“But I’ll need something more.”

She then pointed at his crotch.

She couldn’t wait to see her brother’s equipment. Tigra, from what she could see, was big but he was a fully grown adult and he belonged to Cheetara.

She wanted to see what was going to belong to her and hers alone.

She wanted to see what was going to go inside her.

Wilykat didn’t mind.

Afterall, his sister already let him do so much.

He stood up and unceremoniously dropped his pants, showing underwear that were starting to pitch a bit of a tent.

Wilykit was disappointed once again with her brother’s disrobing. She was going to need to train him to make it last a little bit longer, a little bit more of a spectacle and a little bit more teasing so that their next time will be a little bit more enjoyable for her. All the while not realizing that she was already considering the next time she and her brother would have sex.

She concluded that she needed to take things into her own hands.

Wilykat was about to drop his boxers when Wilykit stopped him.

“What?”

“This time, I will do it.”

Wilykit dropped on her knees and grabbed the hem of Wilykat’s boxers with both hands.

She tugged on it before slowly lowering them, revealing bit by bit her brother’s crotch.

She noticed that her brother was starting to get more fur in that area, proof that he was closer to being a man each year.

Soon, she reached the point where she could see part of his dick, then more and more.

Soon all that was left was to free the tip so she decided to yank her brother’s boxers in one go, suddenly fully freeing his dick.

Wilykit was fascinated by her brother’s member, right in front of her.

It was only semi-erected but it was already of a good length.

She wasn’t sure what to do at first, so she asked :

“Kat, Is it supposed to only be like that?” she distinctly remembered that the one she saw before was different in shape, being fully hardened.

“No, it sometimes stands completely up.”

This was the call she needed. She didn’t know what to do but she wanted to see what her brother’s fully deployed dick would look like.

Hesitantly, she reached her hand toward his member. She had one last hesitation before starting to caress it.

She was feeling the texture

Its length,

Its girth.

As it is, it was slightly shorter than the length of her hand.

She delicately yet fully grabbed her brother’s dick, getting to feel its form in her hand. She could feel it getting a bit harder in her hand. It was an enjoyable sensation but she would not dare apply more pressure, fearing she would hurt her brother before she could finish exploring it.

Her attention now centered on the tip of the dick, still covered in foreskin yet looking like it was trying to free itself from it.

Wilykit had an idea. She put both her hands on her brother’s dick.

Wilykat couldn’t help but grunt.

“Sis....”

She was pushing on his dick, trying to pull back the foreskin. It took a few tries but all the while, she was pumping on his dick, inadvertently making him feel good despite the pressure. At the same time it was making his dick harder and harder in Wilykit’s fingers until it was fully erect. As soon as it did, the foreskin completely pulled back and she let go of it.

Wilykit was now looking at her brother’s completely erected dick, fully seeing the tip hidden by the foreskin. She estimated that her brother’s member was now slightly longer than the lenght of her hand.

She then was at a loss as to what to do.

It was the first time she saw a dick this close but she lacked the experience to do anything. She knew her brother was not enjoying it with her only looking at it so she put back a hand on it, surprising her with its stiffness. Although she caressed it, she did not stroke it, not knowing it would have been good for her brother and all she had to go on was that he was trying to hold back grunts.

She looked at the tip, the glans, and noticed a liquid forming up at the tip, precum as she’ll later learn.

She looked at it intensely, like it was daring her to lick it.

She licked it all in a few slow laps.

Wilykat yelped!

His dick was already sensible enough like that. His foreskin was rarely pulled back so just being out in the fresh air of their room made it sensible enough. That his sister was now licking his most sensible part was simply too much for him.

Wilykit felt her brother trying to pull away.

She looked up to him and saw his pleading look.

“Sis...”

Thats when she realized this was a bit too much for him, especially for their first time.

She let his dick go.

Wilykat was still reeling a bit from his sister’s touch when he looked at her. He had expected that she would have completely stood up but he saw she was busy removing her skirt and underwear.

Neither of them had realized before how wet she was as they now saw that her underwear was completely soaked with her juices.

Wilykit had felt moist before but such a flood, proof of her newfound lust for her brother, was new to her.

She flicked her soiled underwear in a corner of the room before standing up fully.

\----------------------------------------------------------------------------------------------

There they were, brother and sister, completely naked; given freely at the sight of the other.

Wilykat looked at his sister’s naked form with a newfound hunger for her yet not certain at knowing what to do.

Wilykit was standing there, her hands behind her and fidgeting. She was still feeling some remnant of shame at her newfound and complete nudity yet there she was, willingly offering her naked self to her brother all the while not being able to help herself from looking at his enticing form either.

They looked in each other’s eyes

“Kit.....”

“Kat....”

As the previous times, before her brother’s hesitation, Wilykit was the first to act.

She walked beside her brother, her tail balancing slowly in what she hoped to be an inviting way and her face harbouring what she also hoped was a sultry look. She gave him a little kiss on the lips before directing herself toward the bed.

She knew what she had to do.

When she spied on Cheetara and Tigra, Cheetara was on top of him and it looked wild and passionate. When her brother spied on Lion-O and Pumyra, Lion-O was on top and they were in an intimate and loving embrace.

Wilykit wasn’t ready for something wild; she wanted something more intimate with her brother. She wanted to fully feel his love...

She laid down on her back on the bed, trying to have an inviting pose and expression for her brother.

It seemed to work because when Wilykat looked at her naked form, his member seemed to pulsate at her and his eyes couldn’t let go of her inviting body.

“Gods youre beautiful!”

Wilykat moved himself toward the bed and climbed on it.

Just like when Wilykit kneeled down to examine his dick, she now was in the perfect position for him to head down and examine her pussy.

Wilykit couldn’t help but blush at the idea of her brother exploring her most intimate parts yet she had a certain excitement at the idea that she would now have nothing left hidden for him.

After pushing aside her tail so it wouldn’t be in the way, Wilykat had his face very close to his sister’s pussy.

He was admiring her cute and beautiful shape, its lips and its soft inviting color. He directed his hands toward it before hesitation gripped him. He looked at his sister, as if looking for permission, which she gave with an approving look.

He delicately caressed his sister’s sex, not wanting to cause her pain, his delicate touch magnifying her sensations. Event tough he saw how wet she was, the transparent liquid leaking out of her sex didn’t scare him and he gladly accepted his fingers being covered in it.

He explored her closed lips and rubbed the little slit between them. He smiled : he could hear Wilykit starting to make little noises.

It was time : he delicately and slowly opened her pussy lips, like he was opening a uniquely precious gift. And it was

His sister’s pussy was now bare to his sight, offering her inner folds to him. He appreciated its pink color passing before his fingers as he touched its interior, all the while her little noises were getting slightly louder. He observed two holes in it : one small and one bigger. He guessed that the one closer to the outside must be the girl’s pee hole while the other could only be THE hole.

The hole where he will be

The hole where his sex will meet hers.

The place where Wilykat and Wilykit, brother and sister, will be united in a final incestuous embrace.

While he was continuing in caressing the interior of Wilykit’s pussy, he didn’t know that she would have preferred him to be a little rougher with it. She felt that the enjoyable sensations she was now feeling would have been more intense if he did.

However, she didn’t want to detract her brother from his exploration. He didn’t say anything when she was doing the same thing so she strived to do the same, not knowing this attitude was simply stifling her pleasure.

It might not have been such a great idea but the Thunderkittens simply did not know better due to their inexperience and their general awkwardness in this situation.

Wilykat decided to consider more of his sister’s wetness, of which he got an idea. Just like when she licked the tip of his dick of its liquid, so will he. However, remembering his extreme sensibility to that (his own dick seemingly throbbing in agreement), he closed her pussy lips and decided to lick all the juice that had leaked outside.

He decided to start with her inner thighs, going as close to the bed as he could without lifting her and licked the liquid back to its source.

Although it was still early in their sexual session and it would be greatly dwarfed later, Wilykit already felt overwhelmed by the amazing sensations brought by her brother’s great idea. She felt her body getting electrified by the sensations of pleasure brought on by her brother’s licking. It was even more intense when he finished cleaning her inner thighs and started on licking her pussy’s exterior.

Wilykit felt drops of pleasure each time her brother licked her pussy, but that was nothing compared to when he decided to clean the inside of it. Wilykat had decided to lick the entrance of his sister’s pussy by sticking his tongue inside her pussy but without opening it. Judging by the moans that Wilykit was now producing, he felt he was on the right track.

Compared to when her brother licked her thighs, him licking the inside of her pussy brought on a river of pleasure toward her.

She also felt something new, like it was just the tip of something leading to a grander ocean of pleasure, something that existed that she was only now aware of.

However, just as fast as that sensation came, it stopped, for her brother had finished his “cleaning”, even though more of her moist flooded out immediately, especially after such sensations.

Wilykat then came upon a little nub hidden near the top Wilykit’s outer lips, the clit as he’ll later learn.

He started playing with it, like he did with Wilykit’s nipples while being careful to not be too rough.

Wilykit’s noises changed when he started touching it.

Was she.... cooing?

In all cases, Wilykat found that the noises his sister made got more intense everytime he rubbed that little nub. He will have to keep that information in mind for later.

For now, Wilykat was ready to move on from his sister’s pussy and climb back up : he had a trick up his sleeve this time. He had seen Lion-O do that to Pumyra when he was spying on them.

Wilykat was slowly moving up the bed, all the while showering Wilykit’s body with kisses, his sister producing appreciative noises everytime.

His kisses climbed her pelvis.

He kissed her stomach, higher and higher.

He soon reached her breasts and wanted to suck her nipple one more time. He knew her left breast was sore from the last time so he sucked the other nipple, gentler this time. Her moans were getting a little louder at this sensation.

Wilykat wanted to continue a bit but he felt that was enough for now, that there was more to do for he needed release too.

He continued to shower his sister with kisses as he climbed up her body.

He kissed the mound of her breasts

He kissed her collar

He kissed her neck

He kissed....

He stopped

He was now face to face with his sister, having climbed all the way, panting and sweating.

His throbbing member was now level with her pussy, seemingly hungry to go where it belonged.

He looked into her eyes, filled with love toward him.

She looked into his eyes, filled with love toward her.

She put her hand on his cheek, signifying that she was ready.

Ready for the ultimate step.

\---------------------------------------------------------------------------------------------------------------

Wilykat pulled back, sitting back to make sure he did everything correctly.

Wilykit propped herself on her elbows, for she wanted to see everything from the moment her brother entered her.

She was a bit worried about her insides. She might not know much about sex or the inside of her body but she does remember one time where the Thundercats where fighting Mumm-Ra’s forces and, after some acrobatics, she felt something ripping inside her, inside the place where her brother was now getting ready to enter. After the battle, her underwear were bloodied but it never happened again. Now she was worried that it might indeed happen again.

However, she shoved those negative thoughts aside.

This was a moment of love.

Negativity had no place in it.

She gathered all her courage and squashed those thoughts with it.

Wilykat was getting ready and adjusted his position so he could better enter her.

This was the moment the siblings were waiting for all this time.

Everything before was simply the road to this goal.

The moment when his sex will enters hers.

Wilykat grabbed his hardened member and aligned it carefully with her pussy.

Wilykit didn’t want to miss one moment of this and looked intensively.

The tip finally touched the entrance to her pussy. She thought she was going to jump at that contact but she didn’t. She only felt anticipation.

Wilykat pushed a little harder and her pussy lips parted to allow the entry of his tip.

This is it!

The glans was now fully in and he started to try and push further inside. His current position wasn’t ideal for that however, his inexperience stopping him from figuring out what it was and so he leaned further toward his sister until they were back on top of each other. His sister couldn't keep herself propped up like that and laid back down, unable to see the entry.

Wilykit wanted to see more of it but accepted that she had to rely on her perceptions for that.

To feel it rather than see it.

With the tip now inside and in good position, Wilykat pushed further past the folds inside Wilykit.

He didn’t want to hurt his sister or make her uncomfortable so he went in slowly and carefully.

He somehow felt like he should have met some sort of resistance yet there was nothing of the sort.

All her insides where well oiled by her wetness.

He pushed a little further, with a renewed impatience until he couldn’t anymore.

That was it

He was now completely inside his sister

They were fully connected

He didn’t know what to think at first. He felt good, better than anything he knew before yet he was kinda expecting something like a shock of sensations once he was fully in.

He was starting to worry that he might have done something incorrectly until he looked at his sister’s face.

He witnessed her bliss, her fulfillment at being completely connected to him.

His worries completely melted in front of such contentment and he locked lips with hers in a kiss filled with love.

Wilykit put her arms around his back as if to bring him closer to her than it would already be possible.

The siblings were completely united in every manner possible. In that moment, to them, nothing else existed outside of their lovers’ embrace.

Wilykit and Wilykat separated their lips.

After a moment spent to appreciate their new position, Wilykat returned to the charge with shorter kisses all over his sister’s accessible skin, her arms still embracing him.

Meanwhile, he had started to pump inside his sister’s pussy.

Slowly at first, he almost completely retracted his dick.

Wilykit was worried at first that he would completely be out. She had come to enjoy having this extra girth inside her, it was pushing and touching places she didn’t knew existed before and it felt so good for her.

She was relieved when Wilykat pushed back in before it was completely out, his tip having barely touched back her entrance. He pushed it back in, still slow but faster than the first time. She felt a slight tingle, a slight electric shock of pleasure once it was completely back in.

Then he started going back.

Then forward, faster.

Until Wilykat reached a good rhythm of speed and intensity

Wilykit adapted herself quickly to that rhythm. Waves of pleasure were washing over her each time her brother went fully in, each time faster and more intense. With the sensations she felt matching her brother’s intense thrusts.

Even the movement itself inside her became an enjoyment. Where the slowness of the beginning gave her nothing, this new speed made her feel so good, in a way she could have never fathomed before.

Wilykat had stopped his distribution of kisses to better concentrate on thrusting inside his sister. Her arms had let him go to grab the bed sheets beside her and he had free range to continue pistoning her.

Each time he entered her fully, she moaned of pleasure.

Each time he slammed back in, she moaned louder.

He continued to experiment in speed and intensity until he reached what he felt was a good rhythm.

They continued like that for a good time.

Wilykat was pumping his sister with all his body and soul.

Wilykit was receiving her brother with all her being.

All the while he was pumping; Wilykat felt a new sensation, as if all his pumping was building up toward something, toward a sort of release. He wasn’t sure what it was but it was coming.

He remembered from his spying that a couple’s intensity run toward a paroxysm of intensity, a sort of crescendo of moans.

He felt his release slowly but surely approaching. However, Wilykit’s moans, while intense, were stable.

He knew he had to do something to not leave his sister behind. He tried to restart kissing her but it was hard to do with such movement and without his speed suffering from it.

Then he remembered her little nub near her pussy that seemed to magnify her sensations. He didn’t know if it wasn’t already being rubbed upon, considering how close their bodies now are, but he had to try! To try and touch it despite the awkwardness of their position.

Meanwhile, Wilykit was hit by wave after waves of pleasure and sensations with each movement. She was feeling like a sailor, sailing toward an unimaginable ocean of pleasure, something she could now see within her grasp yet still so far.

If only she could get past that coast, that limit, that edge! and sail toward those high seas of sensations...

Each wave of pleasure

Each pumping of her brother

Each time he slammed his dick back inside her in a wet slap

Everything brought her closer to that goal, slowly but surely.

But she wanted to go faster!

At first she wiggled her hips to see if there was a slightly better position, something that would bring her closer to that but no, their union was already perfect as it was.

Until she noticed that her brother was trying to wiggle, to reach something down there with his hand.

She understood immediately.

Wilykat, by having one of his hand trying to reach Wilykit’s clit, became somewhat unstable with only one arm to steady himself over her, having his body pressing more on hers’. The added weight on her body was getting distracting for her.

Thankfully, Wilykit quickly noticed his plight and allowed him to steady himself with both arms once again, allowing him to concentrate on pumping up his sister.

Wilykit’s hand had reached the little nub of her clit, her brother having raised himself to allow her better access.

She then rubbed furiously; magnifying everything she already felt : her sensations, her pleasure and her love.

Each time her brother slammed back in made her hand move in rhythm with it. This was like putting her sailboat of sensations on the turbo toward that unknown ocean of pleasure.

She soon felt her brother’s rhythm becoming more erratic.

She understood.

He was going to soon reach a release, just like her.

She felt confident that she was close enough to her own release to let go of what she was doing, allowing her brother to come back down, closer to her.

She had unconsciously started to raise her legs, as if about to grab Wilykat in a pincer to forbid him from ever leaving her.

Wilykat’s pistoning was gradually becoming more and more erratic.

He felt his release coming, becoming more and more urgent, like a biological imperative to breed the girl before him. He could not understand what it was but he knew he would soon be at his paroxysm, at the climax of his sensations.

He was trying to hold back, a bit afraid of what that unknown release truly entailed but mostly for Wilykit’s sake.

He wanted their climax to happen together.

He held back just enough so that he could feel his sister’s paroxysm joining his level. He soon felt Wilykit’s hand leaving the space between them, allowing him to finally close the last scrap of space between their bodies.

He felt her arms around him

He felt her breasts under him

He felt her breath beside him

He heard her screams of pleasure

He felt her legs locking him in place, bring himself into her deepest reaches.

He could not hold back anymore, he simply let go

It felt like a dam broke, finally releasing a flood of sensations, of love and lust intertwined together.

And more

He cummed in his sister

Again and again as his sister moaned in pleasure, the loudest he heard her ever since they started.

He cummed in the deepest parts of his sister, flooding her insides with it like a raging torrent, reaching her uterus with his incestuous seed and repainting it entirely white.

The sensations of his release, of his cumming, had overwhelmed him completely.

All he could feel was the sheer intensity of pleasure granted to him by pouring everything he had into his sister’s womb.

Nothing else mattered

Only his complete release inside the girl before him

The biological imperative to breed the girl he was now in

The girl’s body acceptation of the entirety of his seed, of his love

...

However, the stream of incestuous love was not eternal was diminishing gradually.

His mind was starting to come back, even as he poured another bucket of his cum in his sister.

His mind had blanked out when the pleasure overrode his entire being.

He had repainted white his sister’s womb with his seed.

He was now lucid enough to wonder how Wilykit’s climax went, if it was as overwhelming for her as it was for him.

It was

Wilykit had felt near, so very near, all this time.

She felt her brother about to burst inside her.

She didn’t want him to let go

She wanted to be with him

To be close to him once it happened.

To be the closest they could be.

She brought her arms around him so she could feel his body with all she had.

She locked her legs around his waist, to try and push him just a little more inside her.

All she needed to reach this ocean of pleasure she sought was a simple little push.

A push that came in the form of a white stream.

It plunged her into an ocean of pleasure as her orgasm took over her body, electrifying every nerve, every extremities of her body.

It overwhelmed her with unimaginable sensations, a high she never thought possible before.

An ocean of sensations that was colored white as she felt the flood of her brother’s incestuous release pouring inside her, reaching a dept inside her she never knew existed; giving her a sensation of fullness in her womb she never even knew was possible.

Her enjoyment.... her pleasure.... she had reached true bliss.

In that moment, the only thing that mattered was the raging torrent of cum pouring inside her womb and the ecstasy it brought her.

Nothing else

...

Even as she came down from that ocean of bliss, she still found a high in the sensations brought by Wilykat’s cum still streaming inside her.

Her high continued a little more before diminishing in unison with her brother’s, even as his stream lowered before coming down to a few last twitches, before a last few drops of forbidden seed were deposited in her.

She could feel his member softening inside her, liberating a space she was already missing, even as her brother’s cum was trying to flood back out from her womb.

Wilykat had collapsed in fatigue on her, panting heavily, sweating profusely from his exertion.

She feared his added weight on her was menacing to push more of his enjoyable cum out of her womb.

She liked that sensation, that sloshing fullness she never felt before in her womb.

Although she wanted the sensation of his dick inside her a little more, she felt it was more important to try and stifle the flood coming back out.

With a few words and a few looks, he understood.

He fully exits her and proceeded to roll over to the empty space on the bed on her left.

She tried to lift her legs and prop up herself, as if to create a slope inside her to allow the cum to flood back in.

But she couldn’t.

She hadn’t realized how weary she was after all this exertion, her body barely reacting after coming down from her orgasm.

All she could do was to numbingly move her hand to try and block the cum’s exit.

All she got was a handful of her brother’s seed.

Wilykit then shifted her focus elsewhere.

Her womb still felt full of Wilykat’s cum, despite the quantity that was already pooling outside her.

When she looked closely, she could almost see a bump where her uterus is located, as if it was so filled up that it showed.

Or was it just her imagination?

Her body simply felt numb.... and tired..... so very tired.

The high she had felt then had been the best thing she felt in her entire life.

Her and her brother will have to do such an enjoyable activity again.

She couldn’t wait until she has sex with her brother again.

She focused on him : Wilykat was panting and his body was glistening of sweat after such exertion. Only then did she realize that she too was panting and huffing, out of breath after such an orgasm, glistening with beads of sweat all over her.

Wilykat was starting to get a bit cold after sweating so much. But he decided to tough it out, if only just a little bit longer.

He looked at his sister, trying to futilely stop his cum from coming back out of her with her hand. He had soiled his boxers before, after a dream a little bit too intense but never before had he expelled so much, so huge a quantity. It’s as if his body had been building up its reserves for years, precisely for the day it would deposit it all in a girl’s womb.

And what a girl it was.

Wilykit

His sister

His own flesh and blood

The one he loves so much

The one he now loves even more

The one he now loves differently...

More than a sibling... more than a sister.... ....lover

Although he did not know the word “incest”, he knew that things will be different between them from now on. Somehow, this makes him hopeful for the future.

Seeing his sister starting to shiver a bit, he forced his aching body up, grabbing the extra bedcovers that where now rolled up at their feet, to cover their sleepy bodies.

He couldn’t wait until him and his sister had sex again.

**Notes for the Chapter:**

> Hope you enjoyed this.  
> I really tried to portray all the love these two siblings had for one another.  
> Considering how rare this pairing is, i felt it was somehow my duty to make one.
> 
> While there is space for future incest between the two, inspiration has dried out  
> I had this idea that, for the sibling's second sex session, Wilykit had learned about a blowjob and used it to get a big load from her brother, tough much smaller than wilykat's first time. Afterward, they'd both learn that the male body need a period of rest to recharge for a second round. Second round that would end up with wilykat giving a pretty small load to his sister, leaving her totally unsatisfied. They learn the lesson that wilykat simply doesn't have the stamina yet to go multiple rounds with his sister and so, when they have sex, they have to make it count, where they want it.  
> Another idea was that, for whatever reason (its unimportant why), the thundercats have to camp in the woods. So, all three couples isolate themselves at night for sex, leaving only Panthro and snarf at the campfire. However, he'll realize how odd that the thunderkittens also isolated themselves. This could be a step point from where the other thundercats would discover their incest.  
> Of course, being a romantic at heart, i would give them a happy ending with them being accepted.
> 
> For future chapters, I had a CrashXcoco bandicoot smut fanfic in preparation but inspiration dried out before i could write the sex well. as it is, it lays incomplete. i think i would need help to write the sex scene so its a satisfying fanfic


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